Centrifugal device for agitating, spraying and evaporating liquids



June 22, 1965 R. M. NESTER 3,190,344

CENTRIFUGAL DEVICE FOR AGITATING', SPRAYING AND EVAPORATING LIQUIDS Filed Oct. 3. 1960 3 Sheets-Sheet l FIG. 1.

INVENTOR Ralph Mil/e1 N ester ATTORNEY June 22, 1965 R. M. NESTER 3,190,344

CENTRIFUGAL DEVICE FOR AGITATING, SPRAYING AND EVAPORATING LIQUIDS Flled OCT. 3 1960 3 Sheets-Sheet 2' FIG. 2

FIGZB.

FIG. 3

INVENTOR Ralph Mil/er Nester BY 3E ATTORNEY June 22, 1965 R. M. NESTER 3,190,344

CENTRIFUGAL DEVICE FOR AGITATING, SPRAYING AND EVAPORATING LIQUIDS Flled Oct 3, 1960 s Sheets-Sheet s INVENTOR Ralph Miller Nester BY (1 2% 3% ATTORNEY United States Patent 3,190,344 CENTRIFUGA'L DEVKCE FUR AGITATING, SPRAY- ENG AND EVAPBRATENG LIQUIDS Ralph M. Nestor, 8 Crestfield Road, Wilmington, Del. Filed (let. 3, 19.60, v@er. No. 60,015 59 Claims. (Cl. 159-6) This invention relates to an apparatus and a process for evaporation. More particularly, it relates to means for agitating, spraying and evaporating.

in many commercial operations as well as in laborat-ory processes, it is frequently necessary to concentrate a solution or to convert the solids in a given liquid mixture to a viscous state or to a dry state. Very often these conversions are done with conventional stir-rers, vacuum apparatus, spray driers and the like. However, there are many instances in which an exceptionally highly dried or solvent-free state is desired or in which organic or other materials need to be so concentrated or dried with the application of a minimum amount of heat. In addition to apparatus for the accomplishment of exceptionally rapid concentration, there is need for apparatus which is readily assembled and disassembled for ready cleaning without appreciable loss of the desired concentrate or separated materials.

Thus, an objective of this invent-ion is the provision of apparatus by which mixtures may be readily separated. A further objective is providing an apparatus which may be driven or rotated in the mass to be treated, and which, in said rotation, forces the mass into thin layers .or droplets from which volatile material is readily expelled and collected at a place removed from the remaining concentrated portion. Still further, it is a purpose of this invention to provide a method and an apparatus for spraying liquid mixtures onto surfaces which may be heated to expel the volatile material in the mixture and to provide for the collection of the volatile material separately from the collection of the nonvolatile material. These and other objectives will appear hereinafter.

The objectives of this invention are accomplished by spraying the liquid mixture onto the sections of the walls ,of the vessel containing the mixture which sections lie :above the level of the mixture. This is accomplished by stirring the mixture with a stirrer which has at least one upwardly extending tube which has a spray outlet .or outlets. As the hollow tube is rotated by virtue of its being attached to a rotating main or center rod, the liquid mixture is forced upwardly by centrifugal force. As it is ejected from the tube it is sprayed outwardly toward the walls which are normally, though not necessarily heated. Usually, two such tubes are used, the second being similarly mounted but being a bit shorter than the other. Material coming from the shorter tube commingles with the materials coming from :the longer tube and the coaction leads to a finer spray. Usually the operation is carried out in a closed, evacuated system so that the volatile material present, such as gases, liquids and solids volatile under the prevailing conditions are removed and are condensed or disposed .of as desired. in order to get the last of any material in the bottom of vessels, an agitator aid is usually placed between and below the converging ends of the tubes.

Thus, material at the bottom is forced up the tubes so that there are no residual liquid layers. In certain modifications within this invention the auxiliary agitator is not needed. This is particularly true when a flat bot- 3,19%,34i Patented June 22, 1965 tomed container is used. This invention will be further understood by reference to the drawings which are given for illustrative purposes only and of which FIGURE 1 is a cross-sectional view of an apparatus of this invention in assembled form;

FIGURE 2 shows the tubes in larger detail, FIGURE 2A being a plan and FIGURE 2B being a side elevation of the device of FIGURE 2.

FIGURE 3 is a detailed, detached elevation of a portion of the rotating elements of FIGURE 1, showing the mounting of the agitating portions to the motor; and

FIGURE 4 shows another embodiment of this invention.

As can be seen in FIGURE 1 the flask A, generally made of glass, is equipped with an adapter or top section B. The bottom and top sections are held together by means of rings F, normally of glass, which have aligned circular grooves to receive a suitable circular ring G made of a sealant material such as natural rubber, a synthetic rubber such as neoprene, poly(tetrafiuoroethylene) or similar plastics. These rings are clamped or held together by clamps, not shown, or by the applied vacuum. The adapter part of the evaporator has an inlet C, normally a ground glass joint, for the attachment of an inlet reservoir having a co-joining member through which material may be added during operation. The joint D is also normally a ground joint into which the vacuum bearing tits. The outlet or tube E provides the connection to the vacuum system or aspirator.

The adapter B also has extending downwardly into the bottom section A a bearing R which is tube shaped to receive the rod H with but slight clearance in the lower extremities of the hearing. The rod, usually of metal and normally a tungsten rod, is connected at its top end through vacuum hearing I to motor Z.

It will be noted that the stirrers are of an asymmetrical nature. Therefore, in order .to provide smooth rotation an intermediate spring mounting is used, as shown in FTGUR'E 3. There the vacuum hearing I, which is usually greased in order to increase the ability of the apparatus to maintain a vacuum, is shown about to receive rod H. This rod has at its top end joint {1 which in turn receives the spring P. The other end of spring P similarly fits into the inlet of the adapter 0. These joints at the ends of spring P may be press-fits or if desired they may be held in place by additional fastening means such as bolts or screws. Since rotation of rod on an oit-center basis reduces vacuum capacity, the spring P is used to permit the rotation of rod H centrally and to absorb, as a shock absorber, the asymmetrical rotation of the tubes ,as described below. The other end of adapter O has a cylindrical bore T into which the shaft of motor Z fits and is held in place by set screw S. Thus, it can be seen that with motor Z running rod H is made to rotate.

At the bottom end of rod H is connected an evaporator of this invention, as shown in FIGURE ,1. The evaporator there shown is given in an enlarged form in FLGURE 2. For connection to the rod H the device has a tube M which fits over rod Hat any desired position. Bearing R can be large enough to receive a portion of this tube M but normally this is not required and the upper end of M is positioned a bit below the lower end of bearing 'R as shown in FIGURE 1. The rod Hand tube M are held together for rotation purposes by set screw/collar N. Near the end of .M are mounted the tubes K which in their rotation aiford passage of the map terial L in the flask upwardly into the tubes K and then outwardly against the walls of the fiask. These tubes K I 7 paratus. The time required to etfect complete dryness normally have tapered inlets at the bottom and they may.

have any desired cross-section, as, for example, oval, cir' cular, square and the like. Positioned below the tubes and also rotating with rod H is a spring-like agitator Y which serves to stir the bottommost material in the flask.

While FIGURE 1 shows two tubes only one may be used' or the number may be increased. Several ;tubes 7 similarly mounted are efiectively used for large quantities or witha mass dilficult to agitate. The angle a tube ype of apparatus. I l n P aced in the apparatus of this invent1on using with heating was just short of 40minutes and similar time lengths were needed for the conventional rotating flask The same amount of the said solution the same conditions of heat,'r.p.m. and the like. Complete drying was effected in 20 minutes. The very large timereduction most emphatically demonstrates the efficacy of the method and the apparatus of this invention. Further, the apparatus of this invention avoids the leakage problems that exist in the useof conventional apparatus makes with the vertical is not critical and will vary depending upon the vessels size and shape When multiple tubes are used, they can be at difiierent angles. The tube need not be parallel to H, nor do two opposing tubes have to be in the same planes. r Of two given tubes the plane of one'extending the shortest route toward H intersects the plane of the other similarly extendedas willbe such as the rotating-flask. In another embodiment of this invention still further advantages are attained. As shown in FIGURE 4, a

appreciated from FIGURE 2A. Here again, this arrangement is not required, for the planes may coincideynormally in a two-tube arrangement 'itis'preferred that the tubes not be aligned. By placement in different planes and at different angles various parts of the vessel are swept or treated simultaneously, for the tubes run in different paths. .The tube arrangement and design may be any that resultin liftingof the mass through the tubes followed by the throwing of drops against the wall, flat-' tening them tov form large surface areas, this exposure afiording the higher separation rate attained. In certain instances, particularly with perforated tubes discussed below, the tubes extend first at low angles or substantially horizontally and then bend or curve upwardly; at steeper angles.

In operation, the material is forced upwardly by centrifugalforce into the tubes. The material is then ejected from the tubes and thrown against the walls 'of the flask. These are normally heated by means of a heating mantle or a constant temperature bath, although sometimes they are not, an operator preferring to rely upon the spraying and the vacuum to effect separation. :Very thin'liquid round bottomed vessel U is usedrather. thanja roundbottomed fiask and the container has vertical walls or substantially vertical walls. In certain instances it is'ad- .vantageous to use walls that'are .tapered or slanted, outwardly or inwardly, as this increases the surface area available for the formation of thin layers or for heating 1 the sprayed material. Usually, an outward slant is preferred since this adds further ease to removal of the resultantdried or retained material. While the centrifugal action and suction draw the material to the center, in some modifications the thickness of the bottom, though flat on the outside, 'will be thicker at the edges than at the center, giving the inside bottom surface a cup or saucer-like shape to afford faster flow to the center and hence totube K. r r f a a.

A still further improvementlies in theuse of the perforated tube. Asshown in FIGURE 4, a single tube K is used, this being welded or similarly fixed to the rod H.

V So efficient is this embodiment of this invention that the films are formed in the spraying from which liquid is 1 readily removed by evaporation or volatilization. vapors pass through E to a'trap and are collected by conmain for weighing or ready removal. 7 7

The motor Z may be ofany suitable size and kind and densation or they go to awaste outlet. Non-volatiles rein fact rotation of the rod H and tubes M by hand can be accomplished if desired. Usually, the motor is one the speed of which is constant and canbe set at the desired r.p.m. A motor of 1100 r.p.m. has been used with a variety of materials differing in viscosity. Normally, the metal parts such as the rod and tubes are of tungsten or stainless steel or of some such material that is inert to corrosive materials, and in certain instances they may be constructed of glass.- The spring P is usually made of stainless steel while adapter 0 is normally made of brass. As

(tetrafluoroethylene) *or polyformaldehyde is used. in

making hearing I and the ringseals G. The joinder of the tapered bottom part of Q with thefreceiving tapered portion of bearing -J coupled with the greased tight fitting mentioned above, plastic material such as nylon, polyl conduits.

' agitator Y is not needed with the inletto K positioned. close to the bottom and centered as shown in FIGURE 4.

The tube 4 has orifices or vents V which are positioned on the fixed tube so that they face the walls of thecontainer at any given time. These holes V can be, located throughout the '-full length of the tube; K= though generally the hinged top or aremoval top with gaskets and withclamps.

In'the various forms of containers, including the .round' bottomed flask, the perforated tube can be used with even greater effectiveness than obtained with. the continuous While thisinvention has ben described with particular reference to the use ofa vacuum and toevaporation, it

is' to be understoodthatthe apparatusiand process of this invention may/be used without vacuum being applied.

' In other words evaporation can be eifected at atmospheric of rod H affords a seal capable of maintaining a vacuum of 10-. mm. Hg." In operation the apparatus may be used to separate solutions'or mixtures of liquids,'rnixtures of liquids and solids and mixtures of solids. In such instances there is, of course, a diflierence lin'volatility'in the I materials. being separated, this difierence affording the basis for evaporating or boiling-01f one and not the remainder. The operations to which this rnay' be applied include extraction, simple distillation and spray drying.

pressure. Further, the apparatus may'be employed, as,

for example, in cooking voperations in the kitchen of homes, merely for the great agitation that itaffords.

The apparatus and methods of. this invention have versatility in addition to a high efiiciency. A large variety To illustrate the effectiveness of therapparatus,,;and the method of this invention an aqueous salt solution was placed in a container for drying using a conventional stirrer and conventional evaporating, vacuum distilling ape of mixtures and solutions canrbe quickly-separated. Not

;only is.separationeffectedbut the matter forced to leave a givenspacemay be accurately directed elsewhere for collection or for further treatment, as, for example, with an extractor,,for extraction treatment. The distinct advant'ageof precision-separation in short time periods affords-theresearcher .and' industry methods and devices and results heretofore unavailable. v

, From the foregoing it is apparent that the objectives of this inventionare well accomplished by the provision of a conduit which is rotated in the mixture so'that the centrifugal force applied 'forces the mixture upwardly a? into the tube. The material is then ejected-onto the inner walls of the vessel which are normally heated. The tube is positioned sothat it has an inlet to it located fairly close to the bot-tom of the vessel. It has at least one opening in its lowermost section and at least one opening in its uppermost section, a plurality of "holes in both sections being used in certain embodiments.

In those devices having vents or spray outlets in the uppermost section of the conduit the top end is usually sealed. These vents are positioned so that they face toward the walls of the vessel. In the spraying, :a component of the mixture is converted to a form permitting its removal from the vessel, as, for example, as a vapor which "is pumped out of the vessel and then condensed.

While the invention 'has been disclosed herein in connection with certain embodiments and certain structural and procedural details, it is clear that changes, modifications or equivalents can be used by those skilled in the art; accordingly, such changes within the principles of this invention are intended to be included within the scope of the claims below.

I claim:

1. A device comprising a rotatable member capable of being rotated in a substantially vertical position and having one end adapted for attachment to a driving unit; rotatable with and mounted on and at an angle to said member, a first tube; rotatable with and mounted on said member but at a different place than where said first tube is mounted and at an angle to said member but at an angle different than first said angle, a second tube, said tubes thereby travelling in different paths upon rotation of said member; and in each tube at its end furthermost from the driving end of said rotatable member an opening communicating with the bore in said tube and in each tube near its end nearest the said driving end of said rotatable member at least one opening communicating with the first said opening through said bore.

2. A device comprising a rotatable member capable of being rotated in a substantially vertical position and having one end adapted for attachment to a driving unit; rotatable with and mounted on and at an angle to said member a first tube; rotatable with and mounted on said member but at a different place then where said first tube is mounted and at an angle to said member but at an angle different than first said angle, a second tube, said tubes thereby travelling in different paths upon rotation of said member; and in each tube at its end furthermost from the driving end of said rotatable member an opening communicating with the bore in said tube, said tubes being of different lengths and in each tube near its end nearest the said driving end of said rotatable member at least one opening communicating with the first said opening through said bore.

3. A device comprising a rotatable member capable of being rotated in a substantially vertical position and having one end adapted for attachment to a driving unit; rotatable with and mounted on and at an angle to said member, a tube; rotatable with and mounted on and at an angle to said member but different than first said angle, a second tube, said tubes thereby travelling in different paths upon rotation of said member; and in each tube at its end furthermost from the driving end of said rotatable member an opening communicating with the bore in said tube, said tubes being closed at their ends nearest the driving end of said rotatable member and said tubes having perforations in their sections near said closed end.

4. A device comprising a rotatable member capable of being rotated in a substantially vertical position and having one end adapted for attachment to a driving unit; rotatable with and mounted on and at an angle to said member a tube; rotatable with and mounted on and at an angle to said member but different than first said angle, a second tube, said tubes thereby travelling in different paths upon rotation of said member; and in each tube at its end furthermost from the driving end of said rotatable member an opening communicating with the bore in said tube, said tubes being closed at their ends nearest the driving end 'of said rotatable member and said tubes having perforations in their sections near said closed end communicating with said opening through said bore and said rotatable member having extending from its end opposite its driving end an auxiliary agitator rotatable with said member.

5. A device which comprises in combination a vessel adapted to hold material; and positioned in said vessel, a rotatable shaft capable of being rotated in a substantially vertical position and having one end adapted for attachment to a driving'unit and having mounted thereon and at an angle "to said shaft at least two tubes to be rotatable with said shaft, said tubes being mounted at different angles to said shaft thereby travelling in different paths upon rotation of said shaft, said tubes being open at their lower ends which are located near the bottom of said vessel, said tubes being of such lengths that their ends furthermost from the bottom of the vessel are near the upper walls of said vessel, and said tubes having an opening at their ends near said walls communicating with the said opening in the lower end through the bore in the tube and being positioned to spray material lifted through said tubes, upon their rotation, against the said walls.

6. A device which comprises in combination a vessel adapted to hold material and containing means for being evacuated during the operation of said device; and positioned in said vessel a rotatable shaft capable of being rotated in a substantially vertical position and having one end adapted for attachment to a driving unit and having mounted thereon and at an angle to said shaft at least two tubes to be rotatable with said shaft, said tubes being mounted at different angles to said shaft thereby travelling in different paths upon rotation of said shaft, said tubes being open at the lower ends which are located near the bottom of said vessel, said tubes being of such lengths that their ends furthermost from the bottom of the vessel are near the upper walls of said vessel, and said tubes having an opening at their ends near said walls communicating with the said opening in the lower end through the bore in the tube and being positioned to spray material lifted through said tubes, upon their rotation, against the said walls.

7. A device which comprises in combination a vessel adapted to hold material; positioned in said vessel a rotatable shaft capable of being rotated in a substantially vertical position and having one end adapted for attachment to a driving unit and having mounted thereon and at an angle to said shaft at least two tubes to be rotatable with said shaft, said tubes being mounted at different angles to said shaft thereby travelling in different paths upon rotation of said shaft, said tubes being open at their lower ends which are located near the bottom of said vessel, said tubes being of such lengths that their ends furthermost from the bottom of the vessel are near the upper walls of said vessel, and said tubes having an opening at their ends near said walls communicating with the said opening in the lower end through the bore in the tube and being positioned to spray material lifted through said tubes, upon their rotation, against the said walls; and means for driving said rotatable shaft comprising a motor and a flexible coupling fixed to said shaft and to the driving shaft of said motor.

8. A device which comprises in combination a vessel adapted to hold material; and positioned in said vessel a rotatable shaft which is capable of being rotated in a substantially vertical position and which has one end adapted for attachment to a driving unit and which has fixed to it for rotation therewith a tube extending at an angle to said shaft and extending toward the walls of said vessel, said tube being closed at its uppermost end, being open at its other end which is positioned near the bottom of said vessel and having in its uppermost section a plurality of perforations which communicate with said opening said tube being closed-at its uppermost end, being open [through said bore and which face the inner Walls of said j References Cited by-theEnaminer d E h i bhaflon a 61 V UNITED STATES PATENTS evlce w c compr ses in com 1 a s v r adapted to hold material; positioned'in, said vessel 9, r0? 60,0197 Waller 259-96 tatable shaft which is capable of being rotated in a sub- 5 V 2 9 stantially verticalpositionand which has one end adapted 2 0 2/08 R 5" 5 for attachment to a driving unit and which has fixed to it asmussen "f'"" 1,744,826 1/ 3 0 Cutler. 1,796,982. 3/31 Cutler.

I FOREIGN PATENTS at its other end which is positioned near the bottom of 950,720 10/5 9 France. said vessel and having in its uppermost section a plurality 494,847 11/38 Great Britain. 7 of perforations which communicate with said opening 1 I throughsaid bore and which face the inner walls of said AN YUDKOFF P r m m vessel; and means to evacuate said vessel during rotation 15 GEORGE D, MITCHELL, CHARLES OCONNELL for rotationtherewitha tube extending at an angle to said shaft and extending toward the walls of said vessel,

of said shaft and the'tuhe fixed'to it. 7 BENJAMIN BENDETT, Examiners; 

7. A DEVICE WHICH COMPRISES IN COMBINATION A VESSEL ADAPTED TO HOLD MATERIAL; POSITIONED IN SAID VESSEL, A ROTATABLE SHAFT CAPABLE OF BEING ROTATED IN A SUBSTANTIALLY VERTICAL POSITION AND HAVING ONE END ADAPTED FOR ATTACHMENT TO A DRIVING UNIT AND HAVING MOUNTED THEREON AND AT AN ANGLE TO SAID SHAFT AT LEAST TWO TUBES TO BE ROTATABLE WITH SAID SHAFT, SAID TUBES BEING MOUNTED AT DIFFERENT ANGLES TO SAID SHAFT THEREBY TRAVELLING IN DIFFERENT PATHS UPON ROTATION OF SAID SHAFT, SAID TUBES BEING OPEN AT THEIR LOWER ENDS WHICH ARE LOCATED NEAR THE BOTTOM OF SAID VESSEL, SAID TUBES BEING OF SUCH LENGTHS THAT THEIR ENDS FURTHERMOST FROM THE BOTTOM OF THE VESSEL ARE NEAR THE UPPER WALLS OF SAID VESSEL, AND SAID TUBES HAVING AN OPENING AT THEIR ENDS NEAR SAID WALLS COMMUNICATING WITH THE SAID OPENING IN THE LOWER END THROUGH THE BORE IN THE TUBE AND BEING POSITIONED TO SPRAY MATERIAL LIFTED THROUGH SAID TUBES, UPON THEIR ROTATION, AGAINST THE SAID WALLS; AND MEANS FOR DRIVING SAID ROTATABLE SHAFT COMPRISING A MOTOR AND A FLEXIBLE COUPLING FIXED TO SAID SHAFT AND TO THE DRIVING SHAFT OF SAID MOTOR. 